Question

Calculate the following in 5.6g of nitrogen

a) Number of moles of N_2.

b) Number of molecules of N₂.

c) Number of atoms of nitrogen.

Answer 1

a) Number of moles of N₂

1. Given the mass of N₂ is 5.6g.

2. The molecular mass of N₂ is 28g.

3. Number of moles is given by = $\frac{\mathrm{Given}\mathrm{Mass}}{\mathrm{Molecular}\mathrm{Mass}}$.

4. Number of moles of N₂ = $\frac{5.6}{28}$

= 0.2 moles

b) Number of molecules of N₂

1. From part a) we came to know that 5.6g of N₂ has 0.2 moles of N₂.

2. Number of molecules is given by = Number of moles x Avagadro's number

= $0.2\mathrm{x}6.022\mathrm{x}{10}^{23}$

= $12.044\mathrm{x}{10}^{23}$

c) Number of atoms of nitrogen.

1. One molecule of nitrogen has 2 atoms of nitrogen, therefore

2. Number of atoms of nitrogen = $2\mathrm{x}\mathrm{Number}\mathrm{of}\mathrm{molecules}\mathrm{of}{\mathrm{N}}_2$

= $2\mathrm{x}12.044\mathrm{x}{10}^{22}$

= $24.088\mathrm{x}{10}^{22}$